Cannabis smoke exposure is not detrimental to lung health and is not associated with the onset of lung cancer, emphysema, or COPD, according to a new study published in the journal Chest.

He reports: “Although regular smoking of marijuana is associated with an increased risk of symptoms of chronic bronchitis and evidence of inflammation and injury involving the larger airways, lung function findings, although mixed, do not provide compelling evidence that habitual marijuana smoking in the manner and amount that it is generally smoked increases the risk of COPD, at least at the population level. Despite the presence of carcinogens in marijuana smoke in concentrations comparable with those that are found in tobacco smoke, the weight of evidence from well-designed epidemiologic studies does not support the concept that habitual marijuana use in the manner and quantity in which it is customarily smoked, when adjusted for tobacco, is a significant risk factor for the development of lung cancer.”

Studies also fail to show a relationship between cannabis smoking and decrements in lung function, and “argue against an association of marijuana with clinically significant emphysema.”

Tashkin’s findings are similar to those of past reviews finding that cannabis smoke exposure fails to possess the same sort of significant adverse pulmonary effects as does tobacco.